The American Trucking Associations’ advanced seasonally adjusted For-Hire Truck Tonnage Index increased 5.7% in August, following a 2.1% decline in July. In August, the index equaled 141.8 (2000=100), up from 134.2 in July. The all-time high was 144 in February.

Compared with August 2015, the index rose 5.9%, the largest year-over-year gain since May, which also came in at 5.9%. In July, the year-over-year increase was 0.2%. Year-to-date, compared with the same period in 2015, tonnage was up 3.5%.

The not seasonally adjusted index, which represents the change in tonnage actually hauled by the fleets before any seasonal adjustment, equaled 144.7 in August, which was 4.8% above the previous month (138.1).

“Volatility continues to reign in 2016. This month’s tonnage reading highlights this fact and underscores the difficulty in determining any real or clear trend in truck tonnage,” said Bob Costello, ATA chief economist. “What is clear to me is that normal seasonal patterns are not holding in 2016.”

Costello noted that during the month of August over the previous three years, the average change in not seasonally adjusted tonnage was just 0.3%. This August, tonnage surged 4.8%.

“Despite a difficult to read August, I expect the truck freight environment to be softer than normal as well as continued choppiness until the inventory correction is complete,” Costello said. “With moderate economic growth forecasted, truck freight will improve as progress is made with the inventory overhang.”